In industrial plants such as e.g. industrial laundries, textile facilities and the like, it is known to use carts for the transport of materials. These carts generally comprise a base and a peripheral wall restrained thereto. Carts for the transport of materials are also generally provided with a plurality of fixed or swivel wheels mounted on the base. A cart for the transport of materials may have various shapes depending on the intended use, for example a polygonal or cylindrical shape. Still depending on the use, the various parts of the cart may be made of different materials, such as, for example, galvanized steel, aluminum, thermoplastic materials and the like. Thermoplastic materials are currently highly employed because they are very cheap and long lasting. Carts made of structurally similar materials are also commonly employed in hotels, hospitals, and communities, for example for the transport of linen to the floors of a hotel or for delivering and collecting materials such as pillows and blankets in airplanes. These carts have a peripheral wall made of a thermoplastic material on whose upper and lower edges respective rounded profiles are fitted and secured. The rounded profiles serve as stiffening means of the cart structure, as well as aesthetic finishing elements. The upper profile also provides an operator with a secure grip when maneuvering the cart, while the lower profile is used to anchor a bottom wall on which the wheels are mounted.
Profiles that are typically used for these purposes are e.g. manufactured by starting from sheet metal plates that are folded so as to achieve a U shape in cross section and that are fixed along the edges of the peripheral wall by way of screws, bolts or rivets.
The base of these carts comprises a plurality of cross members that stretch out between opposite sides of the lower profile and are restrained thereto at their ends. The cross members are generally configured as box-shaped elements that are manufactured by starting from sheet metal plates that are subjected to subsequent cutting and bending operations. The ends of the cross members are shaped so as to match the profile on which they are intended to be fixed, for example they are curved so as to have the shape of a cradle. In order to provide the cross members with a rigidity adequate to the loads and stresses a cart will be subjected during use, further box-shaped elements that are suitably cut, folded and fixed by welding or riveting are employed to reinforce the cross members.
Due to the large number of cutting, bending and assembly operations, the manufacturing of cross members intended to be the supporting elements of the base of a cart of the type described above is rather long and expensive, therefore not suitable for the manufacturing of small groups of carts.
On the other hand, the field of the carts for the transport of materials features a very low level of standardization due to the different uses they are intended to, which determines structures having an extremely variable size and a loading capacity, as well as peripheral profiles and walls that are made of different materials and have various shapes. As a matter of fact, the overall structural configuration must be chosen on a case by case basis.
A further problem of the carts for the transport of materials is that the box-shaped elements used to manufacture the cross members are affected by machining tolerances that are typical of the metallic carpentry, which can make it difficult to assemble them onto the rounded profiles mounted on the lower edge of the peripheral wall of a cart. The peripheral wall in fact is subject to cutting and bending operations as well and thus similarly features the typical tolerances of carpentry.